Most relay testing problems occur because you’re trying to trick the relay into getting a pass by:
- reprogramming the relay, or
- trying to figure out what you need to do to get the relay to go click.
Relay testing suddenly becomes a lot simpler if you simply change your perspective. The power system has four main fault types and relays are designed to respond to specific fault conditions. We can easily simulate three of these fault types with our test-sets, and most test-sets will do the heavy lifting for you if you choose the right test parameters.
Once you start treating your test-set as a power system simulator instead of a relay tester, you can create some simple templates that will test any element in any relay.
Click “Mark Complete” below after watching the video so you can keep track of your progress.
For a phase to phase fault, why does your diagram show a 90 deg lag when you have stated that the fault current should lag by 45 to 85 deg?
Thanks for your question.
The fault current should lag 45 to 89 degrees. You are correct that the P-P fault is at 90 degrees, but I didn’t think anyone who look close enough to notice the 1 degree difference in this video because it’s just an introduction.